1. Field of the Disclosure
The present disclosure relates to a keyless entry system and specifically to a keyless entry system that can suppress the power consumption of an in-vehicle apparatus or a mobile apparatus when the mobile apparatus is not in use.
2. Description of the Related Art
A widely used keyless entry system allows a vehicle operation such as locking/unlocking of the door of a vehicle to be performed without using a mechanical key, by utilizing wireless communication between an in-vehicle apparatus mounted in a vehicle and a mobile apparatus carried by a user of the vehicle. In such a keyless entry system, usually, the in-vehicle apparatus transmits a wireless signal having a frequency (30 kHz to 300 kHz) in the LF (low frequency) band to the mobile apparatus and, in correspondence with this, the mobile apparatus transmits a wireless signal having a frequency (300 MHz to 3 GHz) in the UHF (ultra high frequency) band to the in-vehicle apparatus, thereby performing wireless communication between the in-vehicle apparatus and the mobile apparatus. For example, verification of ID information or transmission and reception of operation information regarding vehicle operations are performed by utilizing wireless communication between the in-vehicle apparatus and the mobile apparatus.
Recently, a keyless entry system, in which an in-vehicle apparatus and a mobile apparatus further include two-way communication means supporting the short-distance wireless communication standard such as Bluetooth (registered trademark) or Bluetooth (registered trademark) Low Energy, and which can send and receive more complex information by utilizing two-way communication between the in-vehicle apparatus and mobile apparatus has been put into use. In such a keyless entry system, the power consumption of the in-vehicle apparatus and mobile apparatus has increased in accordance with an increase in communication functions. Hence, it is preferable that by detecting a state in which the mobile apparatus is not in use (non-use state of the mobile apparatus), part of the communication function of the in-vehicle apparatus or the mobile apparatus be stopped when the mobile apparatus is not in use (non-use time of the mobile apparatus), thereby suppressing power consumption in the in-vehicle apparatus or mobile apparatus.
Proposed keyless entry systems that can suppress the power consumption of an in-vehicle apparatus or a mobile apparatus while the mobile apparatus is not in use include, for example, a smart entry system (keyless entry system) according to Japanese Unexamined Patent Application Publication No. 2012-227586 and a security system (keyless entry system) according to Japanese Unexamined Patent Application Publication No. 2011-184959. FIG. 7 is an explanatory diagram illustrating the configuration of a smart entry system 201 according to Japanese Unexamined Patent Application Publication No. 2012-227586. FIG. 8 is an explanatory diagram illustrating the configuration of a security system 301 according to Japanese Unexamined Patent Application Publication No. 2011-184959.
Referring to FIG. 7, the smart entry system 201 according to Japanese Unexamined Patent Application Publication No. 2012-227586 includes an in-vehicle wireless communication apparatus 210 (in-vehicle apparatus) and a mobile wireless communication apparatus 220 (mobile apparatus). The in-vehicle wireless communication apparatus 210 includes an electronic control apparatus 211 formed of a transmission unit 211a, a reception unit 211b, and a control unit 211c. The transmission unit 211a transmits a wireless signal to the mobile wireless communication apparatus 220. The reception unit 211b receives a wireless signal from the mobile wireless communication apparatus 220. The control unit 211c, in accordance with communication with the mobile wireless communication apparatus 220, controls in-vehicle equipment such as an engine ECU 230, a door lock ECU 231, and the like through an in-vehicle LAN 232.
The mobile wireless communication apparatus 220 includes an LF reception unit 221, an RF transmission unit 222, an operation unit 223, a battery 224, relay switches 225, a vibration power generation device 226, a vibration component determination circuit 227, and a control unit 228. The LF reception unit 221 receives a wireless signal from the in-vehicle wireless communication apparatus 210. The RF transmission unit 222 transmits a wireless signal to the in-vehicle wireless communication apparatus 210. The control unit 228 controls the LF reception unit 221, the RF transmission unit 222, and the like. The battery 224 supplies power to the LF reception unit 221, the RF transmission unit 222, and the like. Power supply to the LF reception unit 221 and the RF transmission unit 222 can be stopped using the respective relay switches 225.
The vibration power generation device 226 outputs a voltage that varies on the basis of vibration transmitted to the mobile wireless communication apparatus 220. The vibration component determination circuit 227 detects a state in which vibration is not being transmitted to the mobile wireless communication apparatus 220 as a non-use state of the mobile wireless communication apparatus 220 on the basis of the output voltage of the vibration power generation device 226. The mobile wireless communication apparatus 220, upon detection of the non-use state of the mobile wireless communication apparatus 220, stops power supply from the battery 224 to the LF reception unit 221 and stops the reception function of the LF reception unit 221.
Referring to FIG. 8, the security system 301 according to Japanese Unexamined Patent Application Publication No. 2011-184959 includes an electronic key 302 (mobile apparatus) and a security apparatus 303 (in-vehicle apparatus). The security apparatus 303 includes a vehicle external transmission circuit 331, a vehicle external transmission antenna 332, a vehicle internal transmission circuit 333, a vehicle internal transmission antenna 334, a reception antenna 335, a receiver circuit 336, and a verification control apparatus 337. The vehicle external transmission circuit 331 transmits a wireless signal to the electronic key 302 through the vehicle external transmission antenna 332. The vehicle internal transmission circuit 333 transmits a wireless signal to the electronic key 302 through the vehicle internal transmission antenna 334. The receiver circuit 336 receives a wireless signal from the electronic key 302 through the reception antenna 335. The verification control apparatus 337 controls various pieces of in-vehicle equipment (not-illustrated) in accordance with communication between the electronic key 302 and the security apparatus 303.
The electronic key 302 includes a reception antenna 321, a receiver circuit 322, a microcomputer 323, a transmission circuit 324, a transmission antenna 325, and a vibration sensor 326. The receiver circuit 322 receives a wireless signal from the security apparatus 303 through the reception antenna 321. The transmission circuit 324 transmits a wireless signal to the security apparatus 303 through the transmission antenna 325. The microcomputer 323 controls the receiver circuit 322, the transmission circuit 324, and the like. The vibration sensor 326 detects whether or not the electronic key 302 is vibrating.
The electronic key 302 stops waiting for a wireless signal from the security apparatus 303 in the case where the doors of a vehicle in which the security apparatus 303 is mounted are locked and where the vibration sensor 326 detects a state in which the electronic key 302 is not vibrating as the non-use state of the electronic key 302, whereby the non-use state of the electronic key 302 is detected.
In this manner, the smart entry system 201 according to Japanese Unexamined Patent Application Publication No. 2012-227586 and the security system 301 according to Japanese Unexamined Patent Application Publication No. 2011-184959, detect the non-use state of a mobile apparatus on the basis of whether or not the vibration of the mobile apparatus exists, and suppress the power consumption of the mobile apparatus by stopping a portion of the communication functions of the mobile apparatus during the non-use time of the mobile apparatus.
Note that in Japanese Unexamined Patent Application Publication No. 2012-227586 and Japanese Unexamined Patent Application Publication No. 2011-184959, a method of suppressing the power consumption of an in-vehicle apparatus is not disclosed, but by detecting the non-use state of a mobile apparatus by using a method similar to that described above, the power consumption of an in-vehicle apparatus may also be suppressed by stopping part of the communication function of the in-vehicle apparatus during the non-use time of the mobile apparatus.
However, in both of the smart entry system 201 in Japanese Unexamined Patent Application Publication No. 2012-227586 and the security system 301 in Japanese Unexamined Patent Application Publication No. 2011-184959, vibration detection means for detecting the vibration of a mobile apparatus is required. Usually, such vibration detection means has a complex configuration, resulting in a mobile apparatus having a complex configuration. This leads to an increase in cost of the mobile apparatus.